We envision developing a new ultrasensitive detection platform that combines a recombinant protein with a unique imaging media that results in a luminescent protein that is non-bleaching and non-blinking. The excitation and emission wavelengths of this protein can be tuned with the choice of imaging media and span much of the visible and near infrared regions of the electromagnetic. We will refer to this new platform as RECAL. RECAL emits light as phosphorescence, but its unique properties result in an overall luminescence intensity that rivals and surpasses many fluorescent organic molecules and can be engineered into a luminescent upconversion probes in which IR excitation will lead to visible luminescence. This will surely allow for the effective use of RECAL as a medical diagnostic tool in tissue, blood, and urine samples or environmental / homeland security devices to name but a few. This proposal has three aims: Aim 1. Develop the RECAL into a microscale ELISA-based medical diagnostic kit for markers associated with liver function and compare its superior sensitivity and marketability to that of state-of-the art ELISA-based medical diagnostic kits in the current market. Aim 2. Test the feasibility of using RECAL as a recombinant in vivo imaging technology and exploit its long luminescent lifetime and photochemical stability to suppress unwanted background in order to increase its sensitivity over existing GFP fusion technologies. Aim 3. Exploit the unique photophysics of associated with RECAL to develop biomolecular imaging technology that absorbs multiple IR photons resulting in visible luminescence. Our goal is to develop commercially viable RECAL products that will have far reaching benefits for medical diagnostics, biomedical research, homeland security, and ultimately human health.